Prismatic Sensors Ab

Martin Sjolin

Mats Danielsson

Mats Persson

Xuejin Liu

Cheng Xu

Staffan Karlsson

Fredrik Gronberg

Christer Svensson

Disclosed is a method for management of geometric misalignment in an x-ray imaging system having an x-ray source, a photon-counting x-ray detector and an intermediate collimator structure in the x-ray path between the x-ray source and the x-ray detector. The x-ray detector includes a plurality of pixels, and the collimator structure includes a plurality of collimator cells, wherein each of at least a subset of the collimator cells corresponds to a N&#xd7;M matrix of pixels, where at least one of N and M is greater than one. The method includes monitoring, for a designated subset of pixels including at least two pixels that are affected differently by shadowing from the collimator structure due to geometric misalignment, output signals from the pixels of the designated subset, and determining the occurrence of geometric misalignment based on the monitored output signals from the pixels of the designated subset of pixels.

Managing geometric misalignment in x-ray imaging systems

Disclosed is a measurement method performed by a Computed Tomography, CT, system. The CT system includes an x-ray source () and an x-ray detector () array of photon counting edge-on detectors (), wherein each photon counting edge-on detector has a number of depth-segments, also referred to as detector elements, arranged at different spatial locations in the direction of incoming x-rays (). The method includes to apply a time offset measurement scheme that provides a time offset between measurement periods for at least two different detector elements located at different depths, wherein the time offset is chosen so that at least two measurement periods at least partially overlaps in time. Disclosed is also a corresponding CT system (), a control unit for a CT system and a measurement circuit for a CT system. A computer program () controlling a CT system is also disclosed. The disclosed technology provides for a higher sampling frequency in the angular direction ().

High-resolution computed tomography using edge-on detectors with temporally offset depth-segments

There is provided a measurement circuit () for an x-ray detector (). The measurement circuit () is configured to sample measurement data to generate data points and process the data points before read-out to produce new data points by combining two or more data points which have been acquired at different times such that the number of data points for read-out are less than the number of original data points.

Measurement circuit for an x-ray detector, and a corresponding method and x-ray imaging system

Disclosed is a detector system for x-ray imaging. The detector system includes a detector having a plurality of edge-on detector modules. Each of the edge-on detector modules includes a first edge that is adapted to be oriented towards an x-ray source and a front-side running essentially parallel to the direction of incoming x-rays. The front-side includes at least one charge collecting electrode. At least a subset of the plurality of edge-on detector modules being pairwise arranged, front-side to front-side, whereby a front-side to front-side gap is defined between the front-sides of the pairwise arranged edge-on detector modules. The pairwise arranged edge-on detector modules are associated with an anti-scatter collimator arranged in the x-ray path between the x-ray source and the edge-on detector modules and overlapping the front-side to front-side gap.

Radiation hard silicon detectors for x-ray imaging

There is provided an arrangement () for enabling assessment of scoliosis. The arrangement () is configured to obtain at least one x-ray image by means of one or more photon-counting x-ray detectors. The arrangement () is further configured to determine at least one characteristic of the spine of a patient having possible scoliosis based on said at least one x-ray image obtained by means of the photon-counting x-ray detector(s) to enable assessment of scoliosis.

X-ray imaging for enabling assessment of scoliosis

There is provided a method and corresponding system for data acquisition, for Computed Tomography, CT, based on an x-ray imaging system () having a detector () with a plurality of pixels (), wherein data sampling is performed with a temporal offset between measurements acquired by adjacent pixels of the detector.

Data acquisition for computed tomography

Disclosed is an x-ray detector system including a multitude of detector elements, each connected to a respective photon counting channel for providing at least one photon count output, and a read-out unit connected to the photon counting channels for outputting the photon count outputs. Each one of at least a subset of the photon counting channels includes at least two photon counting sub-channels, each photon counting sub-channel providing at least one photon count output and having a shaping filter, wherein the shaping filters of the photon counting sub-channels are configured with different shaping times, and wherein the photon counting sub-channels, having shaping filters with different shaping times, are adapted for counting photons of different energy levels. Furthermore, the read-out unit is configured to select, for each photon counting channel, photon count outputs from the photon counting sub-channels.

X-ray detector system based on photon counting

There is provided an x-ray detector including a number of adjacent detector modules arranged in a configuration having central parts and peripheral parts. The x-ray detector is configured to have higher dose efficiency in the central parts and lower dose efficiency in the peripheral parts.

Detector implementations for X-ray detectors

Disclosed are methods, systems, apparatuses and computer programs for estimating a measure of the gain and offset of a converter that generates, based on digital settings, reference voltages to be used as thresholds by a comparator in a photon-counting detector in an x-ray imaging system. Steps include selecting a first converter as a reference converter and a second converter as a target converter; assigning different digital settings to the reference converter to generate at least two different reference voltages to be used as thresholds by a comparator associated with the reference converter; and obtaining, based on photon count measurements, the number of photons registered in a photon counter associated with a comparator whose reference voltage is generated by the target converter. Based on the number of photons and the at least two digital settings, an estimate of the gain and offset of the target converter relative the reference converter results.

Method and system for estimating the relative gain and offset of a converter

There is provided a method for at least partly determining the orientation of an edge-on x-ray detector with respect to the direction of x-rays from an x-ray source. The method includes obtaining (S) information from measurements, performed by the x-ray detector, representing the intensity of the x-rays at a minimum of two different relative positions of a phantom in relation to the x-ray detector and the x-ray source, the phantom being situated between the x-ray source and the x-ray detector and designed to embed directional information in the x-ray field when exposed to x-rays. The method also includes determining (S) at least one parameter associated with the orientation of the x-ray detector with respect to the direction of x-rays based on the obtained information from measurements and a geometrical model of the spatial configuration of the x-ray detector, x-ray source and phantom.

Obtaining measurement information from an edge-on X-ray detector and determining the orientation of an edge-on X-ray detector with respect to the direction of incoming X-rays

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Stockholm, Sweden

Martin Sjolin